The present invention is related to a terminal apparatus for displaying an imaged obtained by a network camera, a method of controlling the terminal apparatus and a computer readable recoding medium.
Recently, image distributing apparatuses have been widely popularized which distribute images when these image distributing apparatuses are accessed via IP networks from a large number of terminal apparatuses. Among these image distributing apparatuses, network cameras on which camera apparatuses are mounted have been widely popularized. Network cameras transmit images imaged by these network cameras to the respective terminal apparatuses, and in a certain case, also transmit voice to these terminal apparatuses by using microphones and speakers, while Web servers are communicated via the IP networks with Web browsers of terminal apparatuses such as personal computers by using, for example, the protocol of HTTP.
In other words, when the Web browsers of the terminal apparatuses are connected via the IP networks such as the Internet, Ethernet (registered trademark), and the like to the network cameras, and then, the Web browsers request image data by using the HTTP protocol, the Web servers transmit display information described in languages such as HTML and XML to the terminal apparatuses. For instance, in the case that a communication operation is carried out by utilizing “Active X” of Microsoft Corporation, a Web browser of a terminal apparatus initiates an image viewer control of “Active X” in accordance with this display information, and then, image data transmitted from a network camera is displayed on an image viewer. As image data transmitted at this time, there are image data of Motion JPEG and MPEG formats, still image data of JPEG format, and the like.
On the other hand, in such network camera systems, in order that images having high resolution of Motion JPEG and JPEG formats are acquired to be displayed on image viewers, lengthy time is required for transferring data on networks. As a result, there are many possibilities that users of terminal apparatuses who request the image acquisitions must wait for long time until these requested images are displayed on these image viewers. In particular, in the case of a moving picture of the Motion JPEG format, the moving picture is adversely influenced by traffic of the network, and thus, an image quality as the moving picture is also deteriorated. Also, even when a user can obtain an image having high resolution, the user may eventually receive useless data, and also, such data, only the partial data of which is required and the remaining data of which is not required, may increase loads of communication traffics.
Although moving pictures are not intended to be transmitted as explained in network cameras, a network print system has been proposed by which even when photographic objects are complex, sharp images of specific portions are obtained, and at the same time, loads of communication traffics are reduced (refer to patent publication 1). In the network print system described in the patent publication 1, in response to an operation input from a terminal apparatus of a user, a plurality of thumbnail images having first resolution are displayed with respect to this terminal apparatus, or a plurality of divided images having low resolution which are produced by dividing an original image by a predetermined frame are displayed thereon by a first display processor provided in a server. When the user selects one sheet of desirable image from either the plural thumbnail images or the plural divided images, such a selected image is transmitted in second resolution higher than the first resolution so as to be displayed, while the selected image is obtained by enlarging either the thumbnail image or the divided image by a second display processor similarly provided in the server.
When a plurality of either thumbnail images or divided images which are independent from each other are received in a high speed, and then, either one thumbnail image or one divided image is manipulated from the terminal apparatus, an original image is displayed instead of either the thumbnail image or the divided image.
As a result, even when the photographic object is complex, the sharp image of the specific portion can be obtained by way of the selection. Moreover, while the loads of the communication traffics can be reduced, and also, the workloads on the operations can be reduced, the image desired by the user can be edited, and then, the edited image can be outputted to such an output device as a printing apparatus.    Patent Publication 1: JP-A-2002-259077
As previously explained, in the conventional terminal apparatus, in order to display the image having the high resolution on the image viewer, the lengthy time is required. Moreover, there are some cases that the image quality of the moving picture is lowered due to the adverse influence caused by the communication conditions. Also, there is such a problem that the data which need not be eventually transmitted may increase the loads of the communication traffics.
As to this terminal point, in the network print system described in the above-explained patent publication 1, plural pieces of either the thumbnail images or the divided images, which own the low resolution, are firstly transmitted in the high speed. When one piece of either the received thumbnail image or the received divided image is manipulated, the original image is displayed. However, this technical idea is merely realized as follows: That is, in the server, the fixed original images are compress-processed by a plurality of fixed frames (areas) respectively in the low resolution, so that either the thumbnail images or the divided images are merely formed. However, this technical idea does not constitute such an idea of a network camera that an image located at an arbitrary position is freely and smoothly enlarged so as to perform a zooming operation.
Then, in the case of the network camera, not only the zooming operation, but also the panning operation and the tilting operation may cause a problem. That is, in the network print system described in the patent publication 1, anyone image of either the thumbnail images or the divided images is merely selected in each frame (area) unit however, in the network camera, the lens must be directed to an arbitrary direction and the user is necessarily required to view this direction. Moreover, the changes in the image produced in connection with this operation must be smoothed. In contrast thereto, in the network print system described in the patent publication 1, while the image is zoom-processed, both the panning operation and the tilting operation are not carried out. In view of this technical point, this network print system has no relationship with the network camera. In other words, the network print system merely selects either the thumbnail image or the divided image, which have been compress-processed in any one of the low resolution, and then, returns the selected image to the original image. It should be understood that such an operation for rotating the view angle of the network camera in the horizontal direction corresponds to a panning operation, whereas such an operation for rotating the view angle of the network camera in the vertical direction corresponds to a tilting operation in this case.
On the other hand, among network cameras, such network cameras capable of optically performing zooming operations, panning operations, and tilting operations are known. These mechanisms are complex and are made expensive. Moreover, since these network systems are operated in the mechanical manner, there are large possibilities that these mechanisms are brought into failure operations, and cumbersome maintenance thereof is also required. Accordingly, in order to popularize network cameras, such a system capable of smoothly performing the above-described zooming, panning, and tilting operations in lower cost by executing software has been desirably expected.